Flame splitting arrangement



United States Patent 3,523,770 FLAME SPLITTING ARRANGEMENT Edward Rahm, Philadelphia, Pa., assignor, by direct and mesn'e assignments, of fifty percent each to Howe-Baker Engineers, Inc., Tyler, Tex., a corporation, and Sun Oil Fompany, Philadelphia, Pa., a corporation of New ersey Filed Nov. 9, 1967, Ser. No. 681,836 Int. Cl. C10g 9/04 US. Cl. 48102 Claims ABSTRACT OF THE DISCLOSURE In a flame-cracking reactor employing an elongated tube of large diameter, wherein a burner flame is directed toward one end of the tube, the flame is split into four (or more) laterally spaced flames, for application to the tube. This splitting is effected by means of a body of refractory material having four or more inclined holes therethrough, which is located between the burner and the adjacent end of the tube.

This invention relates to a flame splitting arrangement.

In the copending Stoops et al. application, Ser. No. 530,979, filed Mar. 1, 1966, there is disclosed a gas generation apparatus wherein fluid (which may be a superheated hydrocarbon vapor) is fed (as make oil) into one end of an elongated tube, toward a flame produced by a burner mounted at one end of the tube. The feed into the tube takes place by way of several tuyeres or nozzles (four in number, for example) whose discharge orifices are directed toward the interior of the tube. As described in said application, the fluid material injected into the tube is treated (cracked) therein to produce a combustible gas, which may be used as a supplement or substitute for natural gas; the tube may therefore be termed a flamecracking reactor.

In a flame-cracking reactor of the type described, it is important, from an efliciency standpoint, that the tuyeres or injection nozzles (which feed the gas to be cracked) be located close to the flame. In a large-diameter reactor, designed for increased throughput, this requirement presents a problem. The tuyeres must remain essentially at the wall of the reactor and cannot be extended toward the center of the tube, since if they were so extended they would be subject to burning as a result of the high temperatures involved. Hence, the flame must be, in effect, brought closer to the tuyeres.

An object of this invention is to provide a novel flamecracking reactor.

Another object is to provide a practical and eflicient design for a flame-cracking reactor of large diameter. A further object is to provide, in a flame-cracking reactor of large diameter, a simple yet effective arrangement for bringing the flame close to the injection nozzles Or tuyeres.

A still further object is to provide a novel flame splitting arrangement for a flame-cracking reactor.

The objects of this invention are accomplished, briefly, in the following manner: A body of refractory material (tile) is placed between a burner, which is firing toward one end of an elongated tube (flame-cracking reactor) and the tube, so as to receive the flame provided by the burner. This body has therein four or more holes of equal ice diameter which are inclined with respect to the common axis of the burner and the tube, and which diverge radial ly outwardly from the burner end of the body. The refractory body causes the single flame of the burner to be split into four or more laterally spaced, axially-inclined, outwardly-diverging flames equal in cross-sectional area, one for each of the four or more injection nozzles of the reactor. In some cases, the cross-sectional area of each of the four flames may equal one-fourth of the cross-sectional area of the original flame; in other cases (such as the four-flame case to be described herein by way of example), the area of each of the four flames is less than one-fourth of the area of the original flame.

A detailed description of the invention follows, taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a longitudinal sectional view of one end of a flame-cracking reactor embodying the invention; and

FIG. 2 is a transverse cross-section taken along line 22 in FIG. 1.

Referring now to the drawing, one end (e.g., the upper end) of an elongated vessel (flame-cracking reactor) 1 is illustrated in FIG. 1. Speaking generally, the reactor 1 may be a telescoped, vertical structure. The outermost shell of the reactor 1 is an elongated vertically-extending tube 2 closed at its upper end by a plate ring 3 having therein a central aperture 4 the diameter of which is quite large, on the order of thirty inches or more, by way of example.

An outer cylindrical metallic wall 6, Whose lower end is secured to the upper surface of ring 3 and which is centered over aperture 4, provides an interior space in which there is provided a suitable heat-insulating material 7 to form a jacket around the upper end of an elongated cracking zone 8. Zone 8 is preferably cylindrical, with a diameter on the order of thirty-four inches, for example.

A ring-shaped plate 9 is secured around its outer diameter to the upper end of wall 6, and the lower end of a cylindrical metallic wall 10 is secured to the interior diameter of plate 9. A ring-shaped end plate 11 is fastened to the upper end of wall 10. The apertured mounting plate 12 of a burner 13 is secured to end plate 11 in any suitable manner, such as by means of bolts (not shown) which extend through the mounting plate 12 and thread into such end plate.

The burner 13 is not shown herein indetail, since per se it forms no part of the present invention. By way of example, it can be a vaporizing oil burner (a high velocity oil burner) having the construction disclosed in Re. Patent No. 24,682, dated Aug. 18, 1959. The fuel is supplied to burner 13 by way of a coupling (not shown) provided on the end of the burner housing opposite to mounting plate 11. Air under pressure (supplied, for example, by means of a suitable blower) is introduced into the burner 13 by means of a pipe (not shown) which is attached to a flanged coupling 14 provided at one side of the burner housing.

An elongated combustion chamber 15, which is formed by an approximately cylindrical refractory lining 16 (made from cut, shaped tiles), extends downwardly from mounting plate 12. The upper end of lining 16 fits within a central aperture (concentric with aperture 4) provided in end plate 11. A cylindrical wall 17 of refractory material, some eighteen inches in length, for example, surrounds the inner lining 16; the upper end of wall 17 abuts the lower face of end plate 11. A cylindrical jacket 18 of heat-insulating material, whose upper and lower ends lie respectively in the same horizontal planes as the upper and lower ends of wall 17, surrounds wall 17. The outer cylindrical face of jacket 18 abuts the inner cylindrical face of metallic wall 10.

The lower end of lining 16 lies in the same horizontal plane as the lower ends of wall 17 and of jacket 18. At its lower end, lining 16 is formed with an outwardly-bevelled surface 19 to provide an increased-diameter central aperture (by a reduction in the thickness of lining 16 in this region).

According to this invention, a block or body 20 of refractory material (tile) is mounted immediately below the lower ends of items 16-18, within wall 10 (and between combustion chamber 15 and cracking zone 8). Body 20 may have a thickness (vertical dimension in FIG. 1) of about eight inches, by way of example, and its lower face lies approximately in the same horizontal plane as the lower face of plate 9. Four or more inclined, radiallyoutwardly diverging holes 21 are provided in body 20, these holes extending through the entire thickness of this body, from the top to the bottom thereof. By way of example, these holes 21 (in the case of four holes) may each have a diameter of 4%", and the centers of the holes are located equidistantly (i.e., 90 apart; see FIG. 2) around the circumference of a common base circle whose center lies on the common longitudinal axis of combustion chamber 15 and cracking zone or tube 8. Arcuate portions of surface 19 from continuations (above the upper face of body 20) of the radially-outer portions of holes 21, so that a smooth entry (for the flame to be split) may be provided at the upper ends of holes 21.

To further this smooth entry feature (at the upper ends of holes 21), a cone-shaped extension member is mounted centrally on the upper surface of body 20, so as to extend upwardly therefrom into the combustion chamber 15. The base of cone 5 is tangent to the four or more circles defining the upper ends of holes 21 (see FIG. 2), and the conical surface of member 5 forms, in eflect, continuations of the radially-inner portions of holes 21. Member 5 is made of a suitable high-temperature-resistant material, such as Carborundum.

Immediately below the lower face of body 20, there is provided a body 22 of refractory material which is approximately of inverted cup-shape, the outer face of the base of the cup abutting the lower faces of items 9 and 20 and the outer side wall of the cup abutting the inner face of jacket 7. The base of the cup 22 has therein four spaced apertures 23 (two of which are visible in FIG. 1) aligned respectively with the bottom ends of the holes 21, and having the same slope.

Near the upper end of cracking zone 8, and approximately midway along the length of wall 6, four or more spaced injection or feed nozzles or tuyeres 24 are mounted in jacket 7. The nozzles 24 are spaced equiangularly (i.e., 90 apart in the case of four nozzles, as illustrated) around the inner cylindrical surface of jacket 7, and are located in individual recesses or pockets provided in jacket 7, just below the lower end of cup 22. The angular locations of nozzles 24 are such that the axis of each nozzle and the center line of a respective one of holes 21 intersect a respective radius which extends horizontally outwardly from the common longitudinal axis of combustion chamber 15 and cracking zone 8.

Since the injection or feed nozzles 24 are mounted essentially at the inner wall of jacket 7, diametricaly-opposite pairs of these nozzles are located a substantial distance apart (on the order of thirty-four inches, for example) measured diametrically across zone 8. A respective conduit 33 (each one of which extends through wall 6 and jacket 7, in a direction approximately at right angles to the longitudinal axis of the reactor 1 and of cracking zone 8) is utilized for each of the four tuyeres 24 disclosed. Each of these conduits 33 is coupled at its inner end to a respective tuyere 24, and at its outer end to a suitable manifold to which is supplied the superheated vapor which is to be injected by the tuyeres into cracking zone 8, and more particularly toward respective flames therein (to be described hereinafter). The feed arrangement for the tuyeres 24, for example, may be somewhat as illustrated in FIG. 3 of the aforementioned copending application. The tuyeres 24 are arranged to inject the make oil in a direction both radially inwardly of the reactor and also toward the upper end of the reactor, at an angle of say 45 above the horizontal, which angle may be variable, if desired.

The combustion chamber 15 has a diameter of about ten inches and a length of about eighteen inches. The burner 13 is of the so-called high heat release type, and is arranged to provide a flame whose lateral extent is commensurate with the diameter of chamber 15, and whose unrestricted or unimpeded length would be substantially in excess of the length of this chamber. When this flame impinges on the refractory body 20 and extension member 5, it is split thereby into four flames, one of which travels down each respective one of the inclined holes 21. Since these holes are inclined radially outwardly from top to bottom of body 20, each one of the four or more flames (into which the original single flame is split) is brought to a region adjacent a respective one of the four or more nozzles 24. As a result, the material injected from each of these nozzles may impinge directly against the tip of a respective one of the four split-flame components. Items 5 and 19 aid the splitting of the single original flame into four flames, by holes 21.

The spatial relation of the split-flame components and the nozzles is illustrated in FIG. 1, wherein the outlines of three of the four flame components are indicated in dot-dash lines at 25, 26, and 27. These flame components (by way of example) may each have an axial length of about fifteen inches, measured from the tip of the flame to the horizontal plane of the lower face of the base of cup 22, and a maximum width of about seven inches (measured at the bulbous or enlarged lower end portion thereof).

The remainder of the flame-cracking reactor 1 (whose lower end is not shown) may be quite similar to that illustrated in FIG. 5 of the aforementioned copending application. The shell tube 2 may have a diameter of sixtyeight inches, for example. concentrically mounted within tube 2 is a pair of spaced, concentric tubes 28 and 29, which are secured at their upper ends to the lower surface of ring 3. The ID. of tube 28 is the same as the diameter of aperture 4, so that tube 28 provides a continuation (downwardly from ring 3) of the elongated cracking zone 8. A cylindrical filling 30 of heat-insulating material is provided between tubes 28 and 29.

A countercurrent cooler-scrubber (not shown herein, but which may have the structure disclosed in the aforementioned copending application) is provided in the annular region between tubes 2 and 29. Uncondensed gases, after traveling down through zone 8 and back up through the aforesaid cooler-scrubber, pass through an opening 31 provided at the upper end of the outer shell 2 into a pipe 32, which conveys them through means such as a demister (as shown in the said copending application) to suitable utilization means.

The invention claimed is:

1. In a flame-cracking reactor, a cylindrical chamber providing an elongated cracking zone, a plurality of injection nozzles each located at the inner cylindrical wall of said chamber, for injecting make oil into said zone, a burner adjacent one end of said zone providing a flame directed toward said one end thereof and substantially along the longitudinal axis of said chamber, and means for splitting said flame into a plurality of separate flames each directed toward a separate respective one of said nozzles.

2. Arrangement according to claim 1, wherein said means is located between said burner and said one end or said zone. I

3. Arrangement set forth in claim 1, wherein said means comprises a body of refractory material positioned between said burner and said one end of said zone and receptive of the flame provided by said burner, said body having therein means for splitting the received; flame into a plurality of separate flames. i

4. Arrangement set forth in claim 1, wherein said means comprises a body of refractory material positioned betweenf'said burner and said one end of said zone, and having a plurality of holes therethrough centered on a common" base circle whose center is located on theflongitudinal axis of said chamber, and a substantially conical refractory member mounted axially on one end face of said body and extending therefrom toward said burner.

5. Arrangement set forth in claim 1, wherein said means comprises a body of refractory material positioned between said burner and said one end of said zone, and having a plurality of holes therethrough centered on a common base circle whose center is located on the longitudinal axis of said chamber.

References Cited UNITED STATES PATENTS 1,773,002 8/1930 Hunt 23-2595 1,847,242 3/1932 Guyer etal. 2,129,269 9/1938 Furlong. 2,140,316 12/1938 Furlong. 2,848,305 8/1958 Lehi er et a1. 23- 277 2,889,209 6/1959 Hale 23-277 JOSEPH SCOVRONEK, Primary Examiner U,S. X.R. 

